When storing data files in folders of a tree structure of a file system, an important issue is to store these files in such a way that they can be accessed without delay, i.e. as quickly as possible. This issue in particular pertains to the provision of data files representing a three-dimensional surface, e.g. a map or images of a terrain, to mobile devices by a remote server.
Computer rendering of three-dimensional terrain images is known from prior art: U.S. Pat. No. 7,551,172 B2 discloses a method for sending information representing three-dimensional images over a network, and U.S. Pat. No. 6,496,189 B1 discloses a method and apparatus for displaying images of an area as seen from an interactively chosen viewpoint on a remote device.
With the methods described in these prior art documents, however, due to inherent limitation on the implementation of the file system, problems can occur that delay the provision of data. In particular, the file system can become unbalanced, i.e. the amount of files per folder can vary considerably, resulting in delayed access times depending on the number of files per folder and the amount of subordinate folders per folder. If a folder contains too many individual files and/or folders, this generally results in slower access and listing times. A well balanced file structure is always faster to access.